Casual anal sex and worried about HIV

Dear Ask The Doctor: I'm an 18 years old guy. I'm not necessarily sexually active, all i've done is receive oral sex twice and received anal sex once. I had sex with a guy who's 28 years old, i didn't know the guy but i did ask if he had any STDs or anything going on with him just to be safe. He answered no and so we got down to business, we had unprotected sex. two days later i saw some bumps on my penis so i two days later after sex i went to planned parenthood to get things checked out, the nurse said it was pearly penile papules on the head of my penis and nothing to worry about, i also got tested for HIV and all those other STDs, all negative.. its been a month now and i'm still worried, every time i think about what i did i get really nervous and think something bad will show up so i start to freak out and feel down on life, feel sick and get the chills. i have read some sympthoms of HIV and they are a lot like the Flu i have had a couple of headaches this month, but i do get headaches once in a while. i had sex with the guy on 6.13.11 and i went back to planned parenthood to ask a few questions, went back today 7.12.11 and i asked about HIV and the nurse told me that if the chances of me getting HIV are really small, specially cause we used lube so that lowers the risk she said.. i wanted to get tested for HIV but she said it was too soon that nothing will show up. i had to wait for another 2 months for that 3 month window and that if i tested negative, that the chances of me not having HIV would be 98% and also to get tested again at the 6 month mark and that after that if i tested negative i would not have HIV at all. i can't sleep at night as i think of me having HIV and how my life would be ruined and that i would die with in years. please help...

Dear German: Getting tested before 3 months have passed may result in an unclear test result, as the infected person may not yet have developed antibodies to HIV. These 3 – 6 months are known as the 'window period'. Many people do not show symptoms after they first get infected with HIV. Others have a flu-like illness within several days to weeks after exposure to the virus. They complain of: fever, headache, tiredness, and swollen nodes in the neck. These symptoms usually disappear within a few weeks. After that, the person feels normal and has no symptoms. This asymptomatic phase may last for years. The development of the disease is different among individuals. The following factors are associated with an increased risk of acquiring HIV infection: Unprotected sex, receptive anal intercourse carries a particularly high risk, injection drug use (sharing needles or drug paraphernalia), occupational needle stick or body fluid splash (estimated transmission rate <0.3%), contaminated blood products (before 1985 in the United States).In your particular case, if you are not sure about the HIV status of the man who you had sex with or if you are feeling very stress out and/or worried, I strongly recommend you getting tested again after the window period.